Electrical adapter unit



1952 T. E. CARROLL ELECTRICAL ADAPTOR UNIT Filed Nov. 10, 1948 I N V EN TOR. ZZdMqsECarra ZZ ATTOR N EY Patented Jan. 1, 1952 UNIT ED S TATE S PAT F F "ICE 2,580,515.; ELECTRICAL ADA211131}, UNiT ThomaslE'. Carroll, New York, N. ,Y: ApplicationNcvemher 10, 1348, Serial No.,5 9,36'l

2 Claims. 1.

This invention relates to an adaptor for enabling electric lamps and other electrical devices having Edison or screw-type bases to be used with outlets or receptacles of the bayonet or bipost types.

In the larger sizes of incandescent lamps, as from 300 watts to 1500 watts, a type commonly referred to in the trade as a bi-post lamp, such as disclosed in Wright Patent No. 2,098,080, is extensively used in theatres, motion picture and other photographic studios, ofiice buildings, gasoline filling stations and on docks and wharves along water'fronts. Because oi the considerable heat generated by'these high wattage lamps when in operation, their contact terminals are in the form of two specially designed studs or-posts such as shown in the aforesaid Wright patent. This terminal construction requires the use of specially designed bi-postsockets for receiving and mounting the lamps, which sockets are permanently mounted in the lighting systems and fixtures where the bi-post lamps are used.

In the Edison or screw-base lamp, as distinguished from the bi-post lamp, there-is a large variety of; different types; including lowwattage lamps, commercially available for different purposes, such as lamps for general illumination purposes, photoflash andphotofiood' lamps, spot lights, enlargers, color lamps and others; It is, therefore, often desired to employ the, screwbase type of lamps in systems orfixtures which are adapted to receive only the bi-post type of lamppr to replace the bi-postlamp with a screwbaselamp, and heretofore it has vbeennecessary to have anelectrician change out the bi-post sockets toeifect this, which in most instances is or receptacles.

Another object of the invention is an adaptor of the character described which contains rela- ,tively few parts, which is rugged in, construction,

and which, is well adapted for quantity production methods and theref re m y be sold at a. ow

price.

O h obj s d. advant g l; be ap r n from the follq i d tai d descrip ion of p s ion in th socket- 2 illustrative embodiment of the invention, taken in connection with the accompanying drawings in which:

Fig. 1 is a view, in elevation, of an adaptor constructed in accordance with the invention, showing its relationship to a bi-post socket and a screw-base type of incandescent lamp, the several units being shown disengaged from each other;

Fig. 2 is a view showing the bottom of the bipost socket illustrated in Fig. 1;

Fig. 3 is a cross-section of the adaptor taken along the line 3 -3 of Fig. 1;; and

Fig. 4 is an exploded view'of the terminal posts, insulating body pieceand inner parts of the assembly comprising the adaptor.

Referring to the upper unit of Fig. l and to Fig. 2, the bi-post socket shown has a body piece In of porcelain or other suitable insulating material, the socket being rigidly secured to an outlet fixture by means of a condulet which comprises a bracket portion H and a sleeve I4 screwed to the end of a conduit [5. Conductors IS in the conduit electrically connect the socket to the lighting circuit. The porcelain body Ill is secured, by means of two machine screws l3, between thebracket I l and a metal clamping ring H. A fibre washer l! between the body In and bracket H" minimizes danger of breakage of the porcelain.

Leaf members 2!} of spring steel are each secured atone end thereof to the porcelain body 10 by means of a machine screw 2| which passes through the fixed end, and the spring members have bayonet slots 20afor receiving the terminals of a bi-post lamp. The terminal posts 34 of my adaptor unit, shown in the middle portion of Fig. l, are therefore of this type. The reduced portions 34a of the adaptor posts enter the curved slots-in the spring members 20 when the adaptor is inserted, and the adaptor is rotated through a small angle, ina.clockwise direction as viewed in Fig. 2, in the same manner as that .in which a bi-post lamp would be inserted. The shoulders formed by the reduced portions 34a of the adaptor terminal post-s engage the ed es ofthe curved bayonet slots 20a and; flex the spring leaf members 20 slightly to provide firm engagement of the upper end of the base 30, Fig, 1, of the adapter with the lower rim 12 0f the bi-post socket, therey to firmly sec re o 9 k t e p o i p r Elec ric on a t. jt e n t a ap o and t e h r-n stsock iis men ed br le s of cur ed, r s contact springs 22 in the socket, which contacts are engaged by the adaptor posts 34 when the adaptor is inserted and rotated in the socket, as above described. Curved clamping members 23 of spring steel apply the proper resilient pressure to the contact springs 22. springs are connected by metal straps 24 and connecting screws 25 to the conductors I 6, the straps 24 being secured to the body I of the bi-post socket by means of machine screws 26.

The adaptor unit of the invention, shown in the middle portion of Fig. 1 and in Figs. 3 and 4, comprises a body portion or base 30 of poreclain or other suitable insulating material with an inner brass screw shell or socket 3| for receiving the screw base of an electric lamp, attachment plug or other electrical device, such as the base 2! of an incandescent lamp 26 shown in the lower portion of Fig. l. The socket 3i may be either of the Mogul size or the medium size, depending upon the size of the lamp to be used. Lamps of the 390 watt size and larger are usually provided with thelarger Mogul screw bases, while lamps smaller than 300 watts usually have the conventional medium size bases. The upper end of the base 30 has two apertures 30a, Fig. 4, with seating portions 332) for engaging and mounting the shoulder portions 34b and for receiving the adjoining reduced portions 340 of the bi-post terminals 34. Preferably, although not necessarily, the length of each of the reduced portions 3&0 is such that when the terminals are inserted in the apertures 35a the ends 01 the reduced portions are flush with or only slightly above the inner surface of the body 30 so that the base 32 of the brass socket 31 may be tightly clamped to the body 38 by means of a machine screw 3-5 which is screw-threaded into one of the terminals 34, thereby also securing the terminal and the I brass socket to the body. The other terminal serted in or removed from the bi-post socket.

The base 32 of the brass shell 3| is electrically connected to one of the terminals 34 by means of the machine screw 35, and the base has a rectangular cutout portion 32a as seen in Fig. 3 to provide clearance for the central brass contact spring 33 of the adaptor socket which is engaged by the center contact 28 of the lamp 2i; of Fig. 1 when the lamp is screwed into the adaptor. The contact spring 33 is electrically connected by means of the machine screw 3'! to the other terminal 34 of the unit. A machine screw 38, which passes through the base of the contact spring and into an aperture of the body The sets of contact 35*, such as shown at 352a in Fig. 4, is tightened aperture above the nut on screw 38. Two other machine screws 46, Figure 3, pass through the base of the brass shell and into apertures in the body 39 and are tightened with threaded nuts to provide additional rigidity to the brass shell, the apertures above these nuts also being sealed with sealing wax.

The body 30 with the apertures 30a and 30c therein is so constructed that it may readily be molded in one piece, and this appreciably reduces the manufacturing costs. Also, the five machine screws 36, 31 and 40 may be of the same kind, size and length if desired, so that only one type of screw need be kept in stock for the assembly of the adaptor unit.

If the screw shell 3| in the adaptor is of the Mogul type and it is desired to insert either a lamp, an attachment plug of an extension cord or other device having a medium size screw base, a reducing plug which has an outer screw shell of Mogul size and an inner screw shell of medium size is commercially obtainable, and such a plug may be inserted in the adaptor unit whereby the devices with medium size screw bases may be used with bi-post sockets of the character described. This enables screw-base lamps of different sizes to be used interchangeably with bipost lamps in a system or apparatus equipped only with bi-post sockets, so that these sockets may be used with a large line of standard lighting and power equipment. The arrangement is particularly advantageous in cases of an emergency where an extension cord or other wire extension is needed, and which otherwise could not be attached to the bi-post socket. The terminals 34 of the adaptor have rounded edges 34d adjacent to the reduced portions 340. which enter the curved slots 26a of the bi-post socket, in order to facilitate insertion and removal of the adaptor in the socket and to prevent binding.

The adaptor of the invention also has the advantage of extendin a screw-base lamp a further distance from the bi-post socket of a device, which is highly desirable in the case of photo-flash or projection type lamps in which the filament of the lamp has to be located at the proper position with respect to the reflector and lens system of the lamp in order to substantially correspond to the position of the filament in a bi-post lamp for which the device was designed, thereby to obtain the correct illumination. This is because the screw-base type of projection lamp has a filament which ordinarily is closer to the lamp base than the filament of a bi-post lamp is to its base. The adaptor therefore is a great convenience to those using photographic flood light and projection equipment of the type which normally employs bi-post lamps, and gives the user of such equipment a wide range of screw-base lamps of which a large variety of different types and sizes are obtainable, thereby making the equipment available for a number of different purposes.

Various modifications of the adaptor unit will readily occur to those versed in the art without departing from the spirit or scope of the present invention which is, therefore, not to be regarded as limited except as indicated by the scope of the appended claims.

What is claimed is:

1. An adaptor unit for connecting a screwbase electrical device to a bi-post socket of the type having bayonet slots and contacts positioned beneath said slots said adaptor unit comprising a preformed body member of insulating material having a closed end with two apertures extending through said closed end, terminal posts respectively having the inner ends thereof extending through and mounted inthe apertures in said body member, the outer ends of said posts projecting from the closed end of said body member and having reduced portions for entering the bayonet slots in the bi-post socket and other portions for electrically engaging the contacts in said socket when the terminal posts of the adaptor unit are inserted and rotated in the bayonet slots, the other end of said preformed insulating body member comprising a skirt portion surrounding a screw-shell socket assembly mounted therein for receiving a screwbase electrical device, the inner ends of the terminal posts each having a portion of larger diameter followed by a portion of smaller diameter and the apertures in the body portion in which the posts are received each having larger and smaller diametral portions respectively contiguous to said portions of the post received therein thereby to seat the post and brace the outer end thereof against lateral forces exerted thereon, and metal clamping members for clamping the posts and the socket assembly to each other and to intervening portions of the insulating body member which form said smaller REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,648,518 Werner Nov. 8, 1927 1,750,006 Henry Mar. 11, 1930 1,946,786 Featherston Feb. 13, 1934 2,090,860 Bonat Aug. 24, 1937 2,385,478 Steinmayer Sept. 25, 1945 2,422,222 Carroll June 17, 1947 

